1. Field of the Invention
Example embodiments relate to a photosensitive polymer. Other example embodiments relate to a photosensitive polymer for a photoresist and a photoresist composition including the same.
2. Description of the Related Art
Due to an increase in the degree of integration of semiconductor devices, numerous techniques for forming finer patterns exist. Some of the techniques are complicated. As such, conventional photoresists require materials having increased properties.
With the recent advent of lithography technology using ArF (193 nm) as a light source, problems occur with the use of conventional photoresist materials. For instance, ArF (193 nm) has a shorter wavelength than KrF (248 nm). Because conventional aromatic materials are absorbed at 193 nm, conventional photoresist materials are difficult to use with the shorter wavelength range of the ArF light source (or any light source with a smaller wavelength) due to a lower resolution.
The use of polymers (e.g., poly(methacrylate) (PMMA)) has been acknowledged. Polymer materials including PMMA are undesirable due to poor etching selectivity in a dry etching process using plasma gas when fabricating a semiconductor. Problems related to etch resistance must be mitigated using various PMMA derivatives (e.g., adamantane derivatives).
2-methyl-2-adamantyl methacrylate (MAMA), which is well-known in the art, is applied to prepare a copolymer functioning as an ArF photoresist. Photoresist materials that include a MAMA monomer do not simultaneously exhibit dry etch resistance and film adhesion.
Functional monomers have been used to increase dry etch resistance and film adhesion. Functional monomers having a variety of lactonyl groups may improve resolution of the photoresist. As such, functional monomers may be used in 100 nm-scale devices. If sub-100 nm devices are formed when the photoresist is thin, then materials capable of exhibiting higher resolution while increasing dry etching properties may be desired.